Abstract
Alternative complement pathway activation occurs through circumvention of regulatory function of β1H and C3bINA. A previous study(Wyatt,et al, J.Lab.Clin.Med.,in press) demonstrated dependence of combined C3 and Factor B (B) levels on β1H and C3bINA levels in normal adults and infants but not in hypocomplementemic glomerulonephritis. Levels were measured by radial immunodiffusion in serial specimens from patients with lupus erythematosus(SLE), acute poststreptococcal(AGN), membranoproliferative (MPGN) and shunt nephritis(SN). Lower limit of normal for C3 is usually considered 2 standard deviations below the normal adult mean; 90mg% in most laboratories. When levels of B, C1H and C3bINA are examined, a borderline(70-110mg%) C3 level is easier to interpret. Ratio of component (C3 + B) to control (β1H + C3bINA) proteins is normal if C3 is depressed on basis of synthesis; if depressed on basis of activation component protein levels will be low relative to control proteins. In AGN and SN component to control ratio (CCR) demonstrates length of time from onset or treatment to cessation of complement activation. In Type I MPGN with 104mg% C3, CCR strongly suggests activation. In SLE, C3 level and CCR do not always concur in indicating complement activation. In conclusion CCR offers a more precise method than use of absolute C3 level for determination of complement activation. CCR may prove of diagnostic importance and aid in judging response to therapy in some nephridites.
Article PDF
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Wyatt, R. USE OF SERUM B1H AND C3b INACTIVATOR (C3bINA) LEVELS IN DETERMINING SIGNIFICANCE OF C3 LEVEL. Pediatr Res 14, 1014 (1980). https://doi.org/10.1203/00006450-198008000-00247
Issue Date:
DOI: https://doi.org/10.1203/00006450-198008000-00247